// g2o - General Graph Optimization
// Copyright (C) 2011 R. Kuemmerle, G. Grisetti, W. Burgard
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef G2O_CACHE_HH_
#define G2O_CACHE_HH_

#include <map>

#include "g2o_core_api.h"
#include "optimizable_graph.h"

namespace g2o {

class CacheContainer;

class G2O_CORE_API Cache : public HyperGraph::HyperGraphElement {
 public:
  friend class CacheContainer;
  class G2O_CORE_API CacheKey {
   public:
    friend class CacheContainer;
    CacheKey();
    CacheKey(const std::string& type_, const ParameterVector& parameters_);

    bool operator<(const CacheKey& c) const;

    const std::string& type() const { return _type; }
    const ParameterVector& parameters() const { return _parameters; }

   protected:
    std::string _type;
    ParameterVector _parameters;
  };

  Cache(CacheContainer* container_ = 0,
        const ParameterVector& parameters_ = ParameterVector());

  CacheKey key() const;

  OptimizableGraph::Vertex* vertex();
  OptimizableGraph* graph();
  CacheContainer* container();
  ParameterVector& parameters();

  void update();

  virtual HyperGraph::HyperGraphElementType elementType() const {
    return HyperGraph::HGET_CACHE;
  }

 protected:
  //! redefine this to do the update
  virtual void updateImpl() = 0;

  /**
   * this function installs and satisfies a cache
   * @param type_: the typename of the dependency
   * @param parameterIndices: a vector containing the indices if the parameters
   * in _parameters that will be used to assemble the Key of the cache being
   * created For example if I have a cache of type C2, having parameters "A, B,
   * and C", and it depends on a cache of type C1 that depends on the parameters
   * A and C, the parameterIndices should contain "0, 2", since they are the
   * positions in the parameter vector of C2 of the parameters needed to
   * construct C1.
   * @returns the newly created cache
   */
  Cache* installDependency(const std::string& type_,
                           const std::vector<int>& parameterIndices);

  /**
   * Function to be called from a cache that has dependencies. It just invokes a
   * sequence of installDependency().
   * Although the caches returned are stored in the _parentCache vector,
   * it is better that you redefine your own cache member variables, for better
   * readability
   */
  virtual bool resolveDependancies();

  bool _updateNeeded;
  ParameterVector _parameters;
  std::vector<Cache*> _parentCaches;
  CacheContainer* _container;
};

class G2O_CORE_API CacheContainer : public std::map<Cache::CacheKey, Cache*> {
 public:
  CacheContainer(OptimizableGraph::Vertex* vertex_);
  virtual ~CacheContainer();
  OptimizableGraph::Vertex* vertex();
  OptimizableGraph* graph();
  Cache* findCache(const Cache::CacheKey& key);
  Cache* createCache(const Cache::CacheKey& key);
  void setUpdateNeeded(bool needUpdate = true);
  void update();

 protected:
  OptimizableGraph::Vertex* _vertex;
  bool _updateNeeded;
};

template <typename CacheType>
void OptimizableGraph::Edge::resolveCache(CacheType*& cache,
                                          OptimizableGraph::Vertex* v,
                                          const std::string& type_,
                                          const ParameterVector& parameters_) {
  cache = 0;
  CacheContainer* container = v->cacheContainer();
  Cache::CacheKey key(type_, parameters_);
  Cache* c = container->findCache(key);
  if (!c) {
    c = container->createCache(key);
  }
  if (c) {
    cache = dynamic_cast<CacheType*>(c);
  }
}

}  // namespace g2o

#endif
